<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT	MIT License
 * @link    https://codeigniter.com
 * @since    Version 2.1.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * PDO Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the query builder
 * class is being used or not.
 *
 * @package        CodeIgniter
 * @subpackage    Drivers
 * @category    Database
 * @author        EllisLab Dev Team
 * @link        https://codeigniter.com/user_guide/database/
 */
class CI_DB_pdo_driver extends CI_DB
{

    /**
     * Database driver
     *
     * @var    string
     */
    public $dbdriver = 'pdo';

    /**
     * PDO Options
     *
     * @var    array
     */
    public $options = array();

    // --------------------------------------------------------------------

    /**
     * Class constructor
     *
     * Validates the DSN string and/or detects the subdriver.
     *
     * @param    array $params
     * @return    void
     */
    public function __construct($params)
    {
        parent::__construct($params);

        if (preg_match('/([^:]+):/', $this->dsn, $match) && count($match) === 2) {
            // If there is a minimum valid dsn string pattern found, we're done
            // This is for general PDO users, who tend to have a full DSN string.
            $this->subdriver = $match[1];
            return;
        } // Legacy support for DSN specified in the hostname field
        elseif (preg_match('/([^:]+):/', $this->hostname, $match) && count($match) === 2) {
            $this->dsn = $this->hostname;
            $this->hostname = NULL;
            $this->subdriver = $match[1];
            return;
        } elseif (in_array($this->subdriver, array('mssql', 'sybase'), TRUE)) {
            $this->subdriver = 'dblib';
        } elseif ($this->subdriver === '4D') {
            $this->subdriver = '4d';
        } elseif (!in_array($this->subdriver, array('4d', 'cubrid', 'dblib', 'firebird', 'ibm', 'informix', 'mysql', 'oci', 'odbc', 'pgsql', 'sqlite', 'sqlsrv'), TRUE)) {
            log_message('error', 'PDO: Invalid or non-existent subdriver');

            if ($this->db_debug) {
                show_error('Invalid or non-existent PDO subdriver');
            }
        }

        $this->dsn = NULL;
    }

    // --------------------------------------------------------------------

    /**
     * Database connection
     *
     * @param    bool $persistent
     * @return    object
     */
    public function db_connect($persistent = FALSE)
    {
        if ($persistent === TRUE) {
            $this->options[PDO::ATTR_PERSISTENT] = TRUE;
        }

        try {
            return new PDO($this->dsn, $this->username, $this->password, $this->options);
        } catch (PDOException $e) {
            if ($this->db_debug && empty($this->failover)) {
                $this->display_error($e->getMessage(), '', TRUE);
            }

            return FALSE;
        }
    }

    // --------------------------------------------------------------------

    /**
     * Database version number
     *
     * @return    string
     */
    public function version()
    {
        if (isset($this->data_cache['version'])) {
            return $this->data_cache['version'];
        }

        // Not all subdrivers support the getAttribute() method
        try {
            return $this->data_cache['version'] = $this->conn_id->getAttribute(PDO::ATTR_SERVER_VERSION);
        } catch (PDOException $e) {
            return parent::version();
        }
    }

    // --------------------------------------------------------------------

    /**
     * Execute the query
     *
     * @param    string $sql SQL query
     * @return    mixed
     */
    protected function _execute($sql)
    {
        return $this->conn_id->query($sql);
    }

    // --------------------------------------------------------------------

    /**
     * Begin Transaction
     *
     * @return    bool
     */
    protected function _trans_begin()
    {
        return $this->conn_id->beginTransaction();
    }

    // --------------------------------------------------------------------

    /**
     * Commit Transaction
     *
     * @return    bool
     */
    protected function _trans_commit()
    {
        return $this->conn_id->commit();
    }

    // --------------------------------------------------------------------

    /**
     * Rollback Transaction
     *
     * @return    bool
     */
    protected function _trans_rollback()
    {
        return $this->conn_id->rollBack();
    }

    // --------------------------------------------------------------------

    /**
     * Platform-dependant string escape
     *
     * @param    string
     * @return    string
     */
    protected function _escape_str($str)
    {
        // Escape the string
        $str = $this->conn_id->quote($str);

        // If there are duplicated quotes, trim them away
        return ($str[0] === "'")
            ? substr($str, 1, -1)
            : $str;
    }

    // --------------------------------------------------------------------

    /**
     * Affected Rows
     *
     * @return    int
     */
    public function affected_rows()
    {
        return is_object($this->result_id) ? $this->result_id->rowCount() : 0;
    }

    // --------------------------------------------------------------------

    /**
     * Insert ID
     *
     * @param    string $name
     * @return    int
     */
    public function insert_id($name = NULL)
    {
        return $this->conn_id->lastInsertId($name);
    }

    // --------------------------------------------------------------------

    /**
     * Field data query
     *
     * Generates a platform-specific query so that the column data can be retrieved
     *
     * @param    string $table
     * @return    string
     */
    protected function _field_data($table)
    {
        return 'SELECT TOP 1 * FROM ' . $this->protect_identifiers($table);
    }

    // --------------------------------------------------------------------

    /**
     * Error
     *
     * Returns an array containing code and message of the last
     * database error that has occured.
     *
     * @return    array
     */
    public function error()
    {
        $error = array('code' => '00000', 'message' => '');
        $pdo_error = $this->conn_id->errorInfo();

        if (empty($pdo_error[0])) {
            return $error;
        }

        $error['code'] = isset($pdo_error[1]) ? $pdo_error[0] . '/' . $pdo_error[1] : $pdo_error[0];
        if (isset($pdo_error[2])) {
            $error['message'] = $pdo_error[2];
        }

        return $error;
    }

    // --------------------------------------------------------------------

    /**
     * Update_Batch statement
     *
     * Generates a platform-specific batch update string from the supplied data
     *
     * @param    string $table Table name
     * @param    array $values Update data
     * @param    string $index WHERE key
     * @return    string
     */
    protected function _update_batch($table, $values, $index)
    {
        $ids = array();
        foreach ($values as $key => $val) {
            $ids[] = $val[$index];

            foreach (array_keys($val) as $field) {
                if ($field !== $index) {
                    $final[$field][] = 'WHEN ' . $index . ' = ' . $val[$index] . ' THEN ' . $val[$field];
                }
            }
        }

        $cases = '';
        foreach ($final as $k => $v) {
            $cases .= $k . ' = CASE ' . "\n";

            foreach ($v as $row) {
                $cases .= $row . "\n";
            }

            $cases .= 'ELSE ' . $k . ' END, ';
        }

        $this->where($index . ' IN(' . implode(',', $ids) . ')', NULL, FALSE);

        return 'UPDATE ' . $table . ' SET ' . substr($cases, 0, -2) . $this->_compile_wh('qb_where');
    }

    // --------------------------------------------------------------------

    /**
     * Truncate statement
     *
     * Generates a platform-specific truncate string from the supplied data
     *
     * If the database does not support the TRUNCATE statement,
     * then this method maps to 'DELETE FROM table'
     *
     * @param    string $table
     * @return    string
     */
    protected function _truncate($table)
    {
        return 'TRUNCATE TABLE ' . $table;
    }

}
